Though this thread is almost 2 and a half years old...this is one of the best posts I've seen recently. The information and descriptions here are very clear cut and paint a great picture. Kudos my friend
I will have to agree from experience, that slipping the clutch is safer and yields better results. I have run my best times in the quarter by slipping on the launch as opposed to dumping. Dumping is just scary and even sounds horrible...so imagine what your gears are saying to you in Gear language when you just dump the clutch?
What the above poster means (at least what I believe he is trying to get across), is that moment of static friction is in the transmission, when the gears are clenched against each other for that millisecond, is when the force is tremendous and has the most potential to start cracking gears: Hence broken trannies in 1st gear on WRXs.